<?php
/* 
 * Copyright (c) 2011 Antoine d'Otreppe de Bouvette
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

class DateTimeFormatter implements Formatter {
    // FIXME: Use UTC time
    const DEFAULT_DATE_FORMAT = 'Y/m/d H:i:s';
    
    /**
     * @var string
     */
    private $format;
    
    public function __construct($format=null) {
        $this->format = $format !== null ? $format : self::DEFAULT_DATE_FORMAT;
    }
    
    /**
     * @param DateTime $value 
     */
    public function format($value) {
        if (!($value instanceof DateTime)) {
            return null;
        }
        else {
            return $value->format($this->format);
        }
    }
    
    /**
     * @param string $value
     * @return DateTime
     */
    public function interpret($value) {
        return DateTime::createFromFormat($this->format, $value);
    }
}
